Abstract: The present invention provides methods, lightweight well cement compositions and additives for the well cement compositions. The methods of the invention for sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressure is basically comprised of the steps of providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising an aqueous suspension of microspheres containing a water swellable clay suspending agent, placing the cement composition in the annulus between the pipe and the well bore and allowing the cement composition to set.

Abstract: A method and composition is provided using whey protein as a retarder in a cementing composition for use in cementing operations in a subterranean zone penetrated by a well bore.

Abstract: A running tool for wiper plugs used in cementing well casings into a wellbore. The running tool and setting balls or darts used to launch the plugs are retrievable following deployment of the plugs. Flapper valve assemblies on the wiper plugs are activated after the plugs are displaced from the running tool to eliminate the requirement to maintain a setting ball or dart in engagement with the wiper plug as the assembly is pumped down the well casing. Because of being retrievable, the mandrel, setting sleeves and setting ball or dart may be constructed of any desirable high-strength material without regard to the need to drill up the material following completion of the cementing job. The use of high-strength steel permits large flow passages to be employed in the cementing plugs by eliminating the need for large volumes of drillable metals in the plugs. The running tool protects the flapper valve seal surfaces from circulating fluids prior to deployment of the plugs from the tool.

Abstract: Methods of cementing in wellbores using cement compositions having elasticity or high compressive strength and low permeability are provided. The cement compositions are basically comprised of particulate acid degradable glass, water, at least one water soluble polymerizable alkenoic acid monomer and a water soluble free-radical initiator.

Abstract: The present invention provides improved foamed well cement slurries, additives and methods. The foamed well cement slurries are basically comprised of a hydraulic cement, sufficient water to form a pumpable slurry, sufficient gas to form a foam and an effective amount of an additive for foaming the slurry comprised of hydrolyzed keratin.

Abstract: An apparatus for preventing or limiting the rotation of cementing plugs in a casing string during drillout. The apparatus includes an outer housing with a sleeve disposed therein. The sleeve has an inner surface configured to engage cementing plugs received therein to cause an interference fit. The sleeve will hold the cementing plugs when rotational forces, such as drilling forces, are applied so that during drillout, rotation of the cementing plug is prevented or is at least limited.

Abstract: The present invention provides light weight high temperature well cement compositions and methods. The compositions are basically comprised of calcium aluminate, ASTM class F fly ash, sodium polyphosphate, a cationic derivatized starch fluid loss control additive and water.

Abstract: In a method and apparatus for transferring material in a wellbore in an earth formation, a pipe is inserted into the wellbore. A conduit is inserted alongside the pipe into the wellbore. The conduit is fixed to the pipe and has a first section with a perforated wall located adjacent a non-production interval of the formation, and has a second section with an unperforated wall located adjacent a production interval of the formation. The material is injected into the conduit and out the perforated wall of the first section of the conduit.

Abstract: A method is disclosed for drilling a wellbore employing a drilling fluid providing the advantages of easy pumpability of a low viscosity fluid with the drill cuttings suspension capability of a highly viscous fluid. The viscosity of the fluid is also easily and quickly adjustable so that the fluid rheology may be adapted during drilling as the subterranean conditions change. These advantages are obtained by including in said fluid a reversibly crosslinkable polymer and an encapsulated crosslink activator. The crosslink activator causes crosslinking after the fluid is in the wellbore. The crosslinking is reversed at the well surface to reduce the viscosity of the fluid to enable the drill cuttings to be easily removed. Crosslink activator is added back to the fluid and the fluid is returned to the borehole. The amount of crosslink activator and/or crosslinkable polymer may be adjusted in the fluid to change the fluid rheology to conform the fluid to changes in the well conditions as monitored real time.

Abstract: Lightweight cement compositions and methods of cementing a subterranean zone penetrated by a well bore utilizing the compositions are provided. A lightweight cement composition of the invention is basically comprised of a coarse particulate hydraulic cement, an ultrafine particulate hydraulic cement mixture comprised of slag cement and a Portland or equivalent cement, fly ash, fumed silica, hollow glass spheres and water.

Abstract: A high temperature viscosifying and fluid loss controlling additive for use in well cements, well cement compositions including the additive and methods of using the compositions are provided. The well cement compositions of this invention are comprised of a hydraulic cement, water and a viscosifying and fluid loss controlling additive comprising a mixture of a polymer comprised of at least one monomer which is calcium tolerant, anionic and disperses basic cement slurries, at least one monomer which hydrolyzes in basic cement slurries to generate anionic carboxylate groups that bind with calcium and viscosify the slurries and at least one monomer which generates non-ionic pendant groups on the polymer upon hydrolyzing in basic cement slurries to prevent polymer precipitation and a homopolymer of a monomer which hydrolyzes in basic cement slurries to generate anionic carboxylate groups that bind with calcium, viscosify the slurries and prevent settling in the slurries.

Abstract: The present invention provides methods and compositions for removing a water-based drilling fluid from surfaces in a well bore and leaving the surfaces water-wet. A method of the invention basically comprises the following steps. A water-based drilling fluid removal solution comprised of water and a mixture of a sulfonated kraft lignin salt and an N-methyl-N-oleyltaurine salt dissolved therein is provided. The drilling fluid is displaced from the well bore and the well bore surfaces are contacted with the removal solution to thereby remove the drilling fluid from the surfaces and make the surfaces water-wet.

Abstract: The present invention provides improved reactive cement compositions for sealing hydrocarbon containing subterranean zones and methods of using the cement compositions. The sealing compositions are basically comprised of water, a hydraulic cement, an organophillic clay, a hydratable gelling agent and a water soluble alkaline source in effective amounts.

Abstract: An environmentally friendly method and composition is provided for removing hydrogen sulphide from fluids at high pH. The method and composition are particularly suited for removing hydrogen sulphide from drilling fluids used in drilling boreholes in hydrocarbon bearing subterranean formations, and are suitable for use with any drilling fluid, including polymer based drilling fluids. The sulphide scavenger used in the method and composition is a ferrous gluconate, an organic iron chelating agent stable at pH as high as 11.5, the pH preferred for drilling fluids that may encounter hydrogen sulphide. Further, this additive has been found to enhance the resilience of the rheological properties of drilling fluids to hot rolling and comparable field conditions.

Abstract: Improved well cement additives, compositions and methods of using the compositions are provided. The well cement additives are basically comprised of a first monomer selected from the group of 2-acrylamido-2-methylpropane sulfonic acid, 2-allyloxy-2-hydroxy-1-propane sulfonic acid and vinylsulfonic acid, a second monomer selected from the group of N,N-dimethylacrylamide, acrylamide, N-vinylpyrrolidone, N-vinylacetamide and acrylonitrile and a third monomer selected from the group of C6 to C22 dimethylaminopropylmethacrylamide bromide, chloride and iodide and C6 to C22 dimethylaminoethylmethacrylate bromide, chloride and iodide.

Abstract: The present invention provides cement compositions comprising an improved fluid loss control additive, and methods for cementing in a subterranean formation using such cement compositions. The cement compositions comprise a hydraulic cement, water, and a fluid loss control additive comprising at least two polymers connected by a pH-sensitive crosslink. Optionally, other ingredients may be included in the compositions.

Abstract: Environmentally acceptable well cement fluid loss control additives, cement compositions including the additives and methods of using the compositions are provided. The environmentally acceptable fluid loss control additives are comprised of ethoxylated hydroxyethylcellulose having a reduced molecular weight.

Abstract: A differential float and cementing valve assembly used to position and cement casing in a wellbore. A leaf spring and other components of the assembly are preferably constructed of composite materials and/or plastics that can be drilled up with polycrystalline diamond compact (PDC) bits. The valve components may be contained within a metallic housing.

Abstract: The present invention provides methods and compressible foamed sealing compositions for sealing expandable pipe in well bores. The compressible sealant compositions for sealing expandable pipe are basically comprised of a hydraulic cement, a rubber latex, a rubber latex stabilizer, a gas and a mixture of foaming and foam stabilizing surfactants.

Abstract: Improved methods of generating gas in and foaming well treating fluids introduced into a subterranean zone are provided. A method of the invention includes the steps of combining one or more gas generating chemicals with the well treating fluid and combining one or more delayed encapsulated activators having selected release times with the well treating fluid containing the gas generating chemicals so that the gas generating chemicals react with the delayed encapsulated oxidizing agent activators and gas and foam are formed in the treating fluid while the treating fluid is being pumped and after being placed in the subterranean zone.